Modification of the Protein Expression Pattern Induced in the Nitrogen-Fixing Actinomycete Frankia Sp. Strain ACN14a-tsr by Root Exudates of Its Symbiotic Host Alnus Glutinosa and Cloning of the sodF Gene

Can J Microbiol. 2001 Jun;47(6):541-7. doi: 10.1139/w01-046.


Two-dimensional (2-D) polyacrylamide gel electrophoresis was used to detect proteins induced in Frankia sp. strain ACN14a-tsr by root exudates of its symbiotic host, Alnus glutinosa. The 5 most prominent proteins were purified from 2-D gels and characterized by N-terminal sequencing. All of these proteins had a high percentage of similarity with known stress proteins. One protein match was the Fe superoxide dismutase (Fe-SOD), another was a tellurite resistance protein (Ter), the third was a bacterioferritin comigratory protein (Bcp); and two matches, differing only by their isoelectric point, were the same small heat shock protein (Hsp), a major immune reactive protein found in mycobacteria. This suggests that the symbiotic microorganism Frankia, first responds with a normal stress response to toxic root products of its symbiotic host plant. To confirm its identity, the gene corresponding to the Fe-SOD protein, sodF was isolated from a genomic library by a PCR-approach and sequenced. It is the first stress response gene characterized in Frankia.

MeSH terms

  • Actinomycetales / genetics
  • Actinomycetales / growth & development*
  • Actinomycetales / metabolism
  • Alnus / microbiology*
  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Cloning, Molecular
  • Electrophoresis, Gel, Two-Dimensional
  • Gene Expression Regulation, Bacterial*
  • Heat-Shock Response
  • Molecular Sequence Data
  • Nitrogen Fixation
  • Plant Roots / metabolism*
  • Sequence Analysis, DNA
  • Superoxide Dismutase / genetics*
  • Superoxide Dismutase / metabolism
  • Symbiosis


  • Bacterial Proteins
  • Superoxide Dismutase

Associated data

  • GENBANK/AJ277540